docs: def isSane(self):
          """
          This method checks the to see if a trust root represents a
          reasonable (sane) set of URLs.  'http://*.com/', for example
          is not a reasonable pattern, as it cannot meaningfully specify
          the site claiming it.  This function attempts to find many
          related examples, but it can only work via heuristics.
          Negative responses from this method should be treated as
          advisory, used only to alert the user to examine the trust
          root carefully.
  
  
          @return: Whether the trust root is sane
  
          @rtype: C{bool}
          """
  
          if self.host == 'localhost':
              return True
  
          host_parts = self.host.split('.')
          if self.wildcard:
              assert host_parts[0] == '', host_parts
              del host_parts[0]
  
          # If it's an absolute domain name, remove the empty string
          # from the end.
          if host_parts and not host_parts[-1]:
              del host_parts[-1]
  
          if not host_parts:
              return False
  
          # Do not allow adjacent dots
          if '' in host_parts:
              return False
  
          tld = host_parts[-1]
          if tld not in _top_level_domains:
              return False
  
          if len(host_parts) == 1:
              return False
  
          if self.wildcard:
              if len(tld) == 2 and len(host_parts[-2]) <= 3:
                  # It's a 2-letter tld with a short second to last segment
                  # so there needs to be more than two segments specified 
                  # (e.g. *.co.uk is insane)
                  return len(host_parts) > 2
  
          # Passed all tests for insanity.
          return True